Motor fuel composition



United States Patent 3,359,088 .MOTOR FUEL COMPOSITION Ronald W. Von Allmen, Hopewell Junction, N.Y., as-

siguor to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Dec. 20, 1965, Ser. No. 515,178 5 Claims. (Cl. 44-72) in which Y represents a radical selected from the group consisting of Y R R RC 0 ..R

and RCR in which R represents hydrogen or a hydrocarbyl radical having from 1 to 12 carbon atoms and the sum of the carbon atoms in 'Y is from 6 to 20, and R is a hydrocarbyl radical having from 6 to 18 carbon atoms.

This invention relates to a motor fuel composition for internal combustion engines having outstanding antiicing, anti-stalling properties. This improvement in the motor fuel is based on the effect of an additive comprising an amine salt of a hydrocarbyl phosphinic acid.

It is well known that spark ignited internal combustion engines employing highly volatile winter grade motor.

fuels are:prone to stalling during engine start-up periods. This problem is generally experienced under atmospheric conditions of high humidity and relatively low temperatures, i.e., humidities above about 70% and temperatures in the range of about 30 to 60 F. Engine stalling under these conditions has beenv attributed to the blocking of the air passage that exists between the carburetor throat and throttle blade during engine idling by the deposition of ice on the internal metal parts of the carburetor. The ice is formed from the water vapor present in the air drawn into the carburetor. This water vapor is condensed and solidified due to the refrigerating effect produced by the vaporization of the motor fuel in the carburetor.

.The stalling. problem noted above is encountered with the use of a. winter grade motor fuel containing a highproportion of volatile hydrocarbons in the gasoline boiling range. The volatility of these fuels is expressed as the Reid vapor pressure. Fuels having a Reid vapor pressure above about 9 and up to about 13.5 are particularly prone to engine stalling due to ice formation under cool, humid atmospheric conditions.

"'A motor fuel cornposition has now been discovered which has substantially improved anti-icing, anti-stalling properties brought about by the addition of an amine salt of a hydrocarbyl phosphinic acid.

In accordance with the invention, there is provided a motor fuel consisting of a mixture of hydrocarbons in the gasoline boiling range containing an effective antiicing, anti-stalling amount of an amine salt of a hydrocarbyl phosphinic acid corresponding to the formula:

in which Y represents a radical selected from the group consisting of in Which R represents hydrogen or a hydrocarbyl radical having from 1 to 12 carbon atoms and the sum of the carbon atoms in Y is from 6 to 20 and R is a hydrocarbyl radical having from 6 to 18 carbon atoms.

The reason why the amine salts of hydrocarbyl phosphinic acids are eflective as carburetor anti-icing agents is not fully understood. It is believed that a molecular layer of the salt adheres to the internal metal surfaces of the carburetor and prevents any build-up of ice on the critical areas thus prevent stalling.

The anti-icing additive of the present invention represented by the formula:

in which Y and R have the values noted above, are prepared by reacting a hydrocarbyl phosphinic acid with a hydrocarbyl amine to form the salt of the invention. The hydrocarbyl phosphinic acid and the amine are reacted in substantially equimolar proportions to produce a product that is essentially neutral.

The preparation of the hydrocarbyl phosphinic acid is accomplished by reacting a solution of a suitable olefin with phosphorus trichloride in the presence of a catalyst as described in the Journal of Organic Chemistry, vol. 27, 1833-4836 and pages 606-609 (1962). In general, the olefin is dissolved in an organic solvent, such as methylene chloride, and a catalyst, such as anhydrous aluminum chloride is added to the solution. A second solution of phosphorus trichloride in methylene chloride is then added to the first solution. The solutions are mixed together at a low temperature, generally below 5 C., and then the mixture is brought to about 25 C. at which temperature the reaction is completed. The reaction product is hydrolyzed and the organic layer separated, washed with water and the solvent distilled off. The residue is refluxed with a 10% caustic solution, acidified with concentrated hydrochloric acid and the phosphinic acid extracted into a solvent, such as diethyl ether. The ether solution is washed with water, the ether evaporated and the product azeotropically dried with a solvent, such as benzene.

In the preparation of the hydrocarbyl phosphinic acid, two different ring structures are possible depending on the type of olefin employed. Alpha olefins lead to the formation of hydrocarbyl phosphinic acids having the formula:

i... RC R wherein R has the values given above. Internal olefins produce a hydrocarbyl phosphinic acid having the formula:

wherein R has the values noted above. Olefin mixtures will produce mixtures of the phosphinic acids containing acids of both structures.

In general, olefins are employed which will produce a hydrocarbyl phosphinic acid which is soluble in a motor fuel composition. Thus, the divalent radicals in the hydrocarbyl phosphinic acid, depicted as Y above, will have a total number of carbon atoms ranging from 6 to 20, and preferably from about 9 to 15. The olefins which can be employed are the aliphatic olefins. Specific olefins which are suitable include propylene dimer, propylene trimer, propylene tetramer, propylene pentamer, ethylene tetramer, ethylene pentamer, butylene dimer, butylene trimer, butylene tetramer and the like.

The amines which can be employed in the formation of the salt are represented by the formula:

in which R is a hydrocarbyl radical having from 6 to 18 carbon atoms. Suitable hydrocarbyl amines include hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine and the like.

The amine salt of a hydrocarbyl phosphinic acid is effective as an anti-icing, anti-stalling agent in gasoline in a concentration ranging from about 0.001 to 0.1 weight percent. A preferred concentration level is in the range of 0.003 to 0.01 weight percent, an amount corresponding to approximately between 8 and 30 pounds of additive (p.t.b.) per thousand barrels of gasoline.

The anti-icing, anti-stalling effect of amine salts of hydrocarbyl phosphinic acids in motor fuels was evaluated in a carburetor icing demonstrator apparatus consisting of a vacuum pump equipped so that cool moisturesaturated air from an ice tower is drawn through a simple glass tube gasoline carburetor. The gasoline sample is placed in a sample bottle and is drawn into the glass carburetor through a hypodermic needle which is 20 gauge in size. Evaporation of the gasoline in the glass tube further cools the cold moist air with resulting ice formation on the throttle plate. The formation of ice on the throttle plate causes the engine to stall and it has been found that this condition is equivalent to a pressure drop across the throttle plate of about 0.5 inch of mercury. In the test, the time to reach 0.5 inch of mercury pressure drop is recorded. The vacuum pump is adjusted to give a vacuum of 1.8 inches of mercury and the test is run until a pressure of 2.3 inches of mercury has been reached or is run for 300 seconds. Since with most fuels this pressure drop is reached in 1 to 4 minutes, 300 seconds is the maximum time for a run. A recording of 300 seconds indicates no stalling within the test period. Each fuel is run three times in succession and the average is recorded. If the diiference among the runs are great, the glass tube carburetor and the test throttle are washed with alcohol, flushed out with gasoline and the runs repeated. A leaded winter grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in under 100 seconds in this test. Additives which raise the stalling time to over 200 seconds are regarded as effective anti-stalling, anti-icing additives.

The base fuel employed in the example below to evaluate the effectiveness of the amine salts of hydrocarbyl phosphinic acid was a winter grade premium gasoline having an ASTM research octane rating about 99.0 containing 3.07 cc. of TEL per gallon. This gasoline had a 50% ASTM distillation point of 230 F. and a Reid vapor pressure of 11.0 lbs.

One hundred grams (0.59 mole) propylene tetramer, dissolved in cc. methylene chloride, was added dropwise over a period of 2 hours to a slurry of 150 g. (1.12 moles) of anhydrous aluminum chloride, g. (1.2 moles) of phosphorus trichloride and 600 cc. methylene chloride. During the addition, the reaction was kept below 5 C. by means of an ice-salt bath. The cooling bath was removed, the mixture allowed to come to 25 C. and held there for one hour. The cooling bath was replaced and the mixture partially hydrolyzed by slowly adding 500 cc. methanol followed by 500 cc. water. The temperature was kept below 15 C. during the hydrolysis. The organic layer was separated, washed with water and the solvent distilled under reduced pressure. The residue was refluxed for two hours with 500 cc. 10% sodium hydroxide solution. The mixture was acidified with concentrated hydrochloric acid and extracted with diethyl ether. This ether solution was washed with water, the ether evaporated, and the product azeotropically dried with,

benzene. The yield of solvent free phosphinic acid, a viscous liquid, was 115 -g., 82% of theory. The product contained 12.2% P (theory, 13.4) and had a total acid number of 239 (theory, 242).

Hexylamine, 10.1 g. (0.1 mole) was added to 23.2 g. (0.1 mole) of phosphinic acid to produce the hexylamine salt of hydrocarbyl phosphinic acid.

Dodecylamine, 18.5 g. (0.1 mole) was added to 23.2 g. (0.1 mole) of phosphinic acid to form the dodecylamine salt of hydrocarbyl phosphoric acid.

The foregoing tests demonstrate the surprising effec tiveness of the amine salts of hydrocarbyl phosphinic acids as anti-icing, anti-stalling additives for gasoline. These additives are effective in both leaded and unleaded gasoline and can be used in conjunction with conventional additives including lead scavenger compounds, metal deactivators, gum inhibitors and dyes.

Obviously, many modifications of the invention, as hereinbefore set forth, may be made without departure from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A motor fuel composition comprising a mixture of hydrocarbons boiling in the gasoline boiling range containing an effective anti-icing, anti-stalling amount of a salt of phosphinic acid and a hydrocarbyl amine corre-- sponding to theformula I Y=1iOH-B1NH2 in which Y represents a radical selected from the group consisting of R R RC\ /0 R 31d ROR\R RC 0 R R in which each R represents hydrogen or a hydrocarbyl radical having from 1 to 12 carbon atoms and the sum of the carbon atoms in Y is from 6 to 20, and R is a hydrocarbyl radical having from 6 to 18 carbon atoms.

2. A composition according to claim 1 containing from 0.001 to 0.1 weight percent of said salt of phosphinic acid and hydrocarbyl amine.

3. A composition according to claim 1 in which said anti-stalling agent is the salt of hexylamine and of hydrocar-byl phosphinic acid obtained by reacting propylene tetramer with phosphorus trichloride.

4. A composition according to claim 1 in which said anti-stalling agent is the salt of dodecylamine and of hydrocarbyl phosphinic acid obtained by reacting propylene tetramer with phosphorus trichloride.

5. A motor fuel according to claim 1 having a Reid vapor pressure above 9.

References Cited UNITED STATES PATENTS 5 3,007,782 11/1961 Brown et a1. 44---72 X 3,087,956 4/1963 Lacoste et a1. 4469 3,095,285 6/1963 Cantrell et a1. 4469 3,228,758 1/1966 Bauer 4469 3,238,277 3/1966 Si'gan et a1. 4469 FOREIGN PATENTS 902,483 8/1962 Great Britain.

15 DANIEL E. WYMAN, Primary Examiner.

P. P. GARVIN, Assistant Examiner. 

1. A MOTOR FUEL COMPOSITION COMPRISING A MIXTURE OF HYDROCARBONS BOILING IN THE GASOLNE BOILING RANGE CONTAINING AN EFFECTIVE ANTI-ICING, ANTI-STALLING AMOUNT OF A SALT OF PHOSPHINIC ACID AND A HYDROCARBYL AMINE CORRESPONDING THE FORMULA 